Method for fabricating a flexible belt with a puzzle-cut seam

ABSTRACT

A flexible electrostatographic imaging member belt comprises two ends with matching puzzle-cut fingers arranged to be joined. The belt is fabricated by a method comprising the steps of: first, joining the two belt ends to form a juncture; second, applying an adhesive layer to the juncture; third, applying a compressing force to the adhesive layer; fourth, heating the adhesive layer for a heating period; fifth, cooling the adhesive layer for a cooling period; thus forming a puzzle-cut seam; and, sixth, determining when the puzzle-cut seam is satisfactory. When it is determined the puzzle-cut seam is not satisfactory, the heating and cooling steps are repeated. When it is determined the puzzle-cut seam is satisfactory, the compressing force is removed. In one embodiment, the method determines when the puzzle-cut seam is satisfactory based on the total time heat is applied to the adhesive layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is related to commonly-assigned application Ser. No. 08/721,418, filed Sep. 26, 1996 by inventors Edward L. Schlueter, Jr. et al., entitled “Process and apparatus for producing an endless seamed belt,” attorney docket number D/96154, now pending. The disclosure of the foregoing commonly-assigned patent application is hereby incorporated by reference verbatim, with the same effect as though such disclosure were fully and completely set forth herein.

FIELD OF THE INVENTION

[0002] This invention relates in general to a low profile seam preparation method and, more specifically, to a thin seam preparation method as well as a post seaming treatment process for flexible imaging member belts application.

BACKGROUND OF THE INVENTION

[0003] Flexible imaging member belts in electrostatographic imaging system are well known in the art. Typical flexible imaging member belt include, for example, electrophotographic imaging member belts or photoreceptors for electrophotographic imaging systems, ionographic imaging member belts or electroreceptors for electrographic imaging systems, and intermediate image transfer belts for transferring toner images used in an electrophotographic or an electrographic imaging system. These belts are usually formed by cutting a rectangular sheet from a web containing at least one layer of thermoplastic polymeric material, overlapping opposite ends of the sheet, and joining the overlapped ends together to form a welded seam. The seam extends from one edge of the belt to the opposite edge. Generally, these belts comprise at least a supporting substrate layer and at least one imaging layer comprising thermoplastic polymeric matrix material. The “imaging layer” as employed herein is defined as the charge transport layer of an electrophotographic imaging member belt, the dielectric imaging layer of an ionographic imaging member belt, and the transfer layer of an intermediate transfer belt. Thus, the thermoplastic polymeric matrix material in the imaging layer is located in the upper portion of a cross section of an electrostatographic imaging member belt whereas the substrate layer being in the lower portion of the cross section of the electrostatographic imaging member belt. Although the flexible electrostatographic imaging member belts of interest include the mentioned types, for simplicity reasons, the discussion hereinafter will be focused on the electrophotographic imaging member belts as the representation.

[0004] Flexible electrophotographic imaging member belts are usually multilayered photoreceptors that comprise a substrate, an electrically conductive layer, an optional hole blocking layer, an adhesive layer, a charge generating layer, and a charge transport layer and, in some embodiments, an anti-curl backing layer. One type of multilayered photoreceptor comprises a layer of finely divided particles of a photoconductive inorganic compound dispersed in an electrically insulating organic resin binder. A typical layered photoreceptor having separate charge generating (photogenerating) and charge transport layers is described in U.S. Pat. No. 4,265,990, the disclosure of the foregoing patent being hereby incorporated by reference verbatim, with the same effect as though such disclosure were fully and completely set forth herein. The charge generating layer is capable of photogenerating holes and injecting the photogenerated holes into the charge transport layer.

[0005] Although excellent toner images may be obtained with multilayered belt photoreceptors, it has been found that as more advanced, higher speed electrophotographic copiers, duplicators and printers were developed, fatigue induced cracking at the welded seam area is frequently encountered during photoreceptor belt cycling. Moreover, the onset of seam cracking has also been found to rapidly lead to seam delamination due to fatigue thereby shortening belt service life. Dynamic fatigue seam cracking and delamination may possibly happen in ionographic imaging member belts as well as in the intermediate image transfer belts.

[0006] The flexible electrophotographic imaging member belts are fabricated from a sheet cut from an imaging member web. The sheets are generally rectangular or parallelogram in shape. All edges may be of the same length or one pair of parallel edges may be longer than the other pair of parallel edges. The sheets are formed into a belt by joining overlapping opposite marginal end regions of the sheet. A seam is typically produced in the overlapping marginal end regions at the point of joining. Joining may be effected by any suitable means. Typical joining techniques include welding (including ultrasonic), gluing, taping, pressure heat fusing, and the like. Ultrasonic welding is generally the preferred method of joining because is rapid, clean (no solvents) and produces a thin and narrow seam. In addition, ultrasonic welding is preferred because the mechanical pounding of the welding horn causes generation of heat at the contiguous overlapping end marginal regions of the sheet to maximize melting of one or more layers therein. A typical ultrasonic welding process is carried out by holding down the overlapped ends of a flexible imaging member sheet with vacuum against a flat anvil surface and guiding the flat end of an ultrasonic vibrating horn transversely across the width of the sheet, over and along the length of the overlapped ends, to form a welded seam.

[0007] When ultrasonically welded into a belt, the seam of flexible multilayered electrophotographic imaging member belts may occasionally contain undesirable high protrusions such as peaks, ridges, spikes, and mounds. These seam protrusions present problems during image cycling of the belt machine because they interact with cleaning blades to cause blade wear and tear which ultimately affect cleaning blade efficiency and service life. Moreover, the protrusion high spots in the seam may also interfere with the operation of subsystems of copiers, printers and duplicators by damaging electrode wires used in development subsystems that position the wires parallel to and closely spaced from the outer imaging surface of belt photoreceptors.

[0008] These closely spaced wires are employed to facilitate the formation of a toner powder cloud at a development zone adjacent to a toner donor roll and the imaging surface of the belt imaging member. Another frequently observed mechanical failure in the imaging belts during image cycling is that the ultrasonically welded seam of an electrophotographic imaging member belt can also cause initiation of cracks in the seam which then propagate and lead to delamination after being subjected to extended bending and flexing cycles over small diameter belt support rollers of an imaging machine or when due to lateral forces caused by mechanical rubbing contact against stationary web edge guides of a belt support module during cycling. Seam cracking and delamination has also been found to be further aggravated when the belt is employed in electrophotographic imaging systems utilizing blade cleaning devices and some operational imaging subsystems. Alteration of materials in the various photoreceptor belt layers such as the conductive layer, hole blocking layer, adhesive layer, charge generating layer, and/or charge transport layer to suppress cracking and delamination problems is not easily accomplished.

[0009] For example, when a flexible imaging member belt used in an electrophotographic machine is a photoreceptor belt fabricated by ultrasonic welding of overlapped opposite ends of a sheet, the ultrasonic energy transmitted to the overlapped ends melts the thermoplastic sheet components in the overlap region to form a seam. The joining techniques, particularly the welding process, can result in the formation of a splashing that projects out from either side of the seam in the overlap region of the belt. The overlap region and spashings on each side of the overlap region comprise a strip from one edge of the belt to the other that is referred herein as the “seam region”. Because of the splashing, a typical flexible imaging member belt is about 1.6 times thicker in the seam region than that of the remainder of the belt (e.g., in a typical example, 188 micrometers versus 116 micrometers).

[0010] The photoreceptor belt in an electrophotographic imaging apparatus undergoes bending strain as the belt is cycled over a plurality of support and drive rollers. The excessive thickness of the photoreceptor belt in the seam region due to the presence of the splashing results in a large induced bending strain as the seam travels over each roller. Generally, small diameter support rollers are highly desirable for simple, reliable copy paper stripping systems in electrophotographic imaging apparatus utilizing a photoreceptor belt system operating in a very confined space. Unfortunately, small diameter rollers, e.g., less than about 0.75 inch (19 millimeters) in diameter, raise the threshold of mechanical performance criteria to such a high level that photoreceptor belt seam failure can become unacceptable for multilayered belt photoreceptors. For example, when bending over a 19 millimeter diameter roller, a typical photoreceptor belt seam splashing may develop a 0.96 percent tensile strain due to bending. This is 1.63 times greater than a 0.59 percent induced bending strain that develops within the rest of the photoreceptor belt. Therefore, the 0.96 percent tensile strain in the seam splashing region of the belt represents a 63 percent increase in stress placed upon the seam splashing region of the belt.

[0011] Under dynamic fatiguing conditions, the seam provides a focal point for stress concentration and becomes the point of crack initiation which is further developed into seam delamination causing premature mechanical failure in the belt. Thus, the splashing tends to shorten the mechanical life of the seam and service life of the flexible member belts used in copiers, duplicators, and printers.

[0012] Since there is no effective way to prevent the generation of localized high protrusions at the seam, imaging member belts are inspected, right after seam welding belt production process, manually by hand wearing a cotton glove through passing the index finger over the entire seam length and belts found catching the glove by the protrusions are identified as production rejects. Both the time consuming procedure of manual inspection and the number of seamed belts rejected due to the presence of high seam protrusions constitute a substantial financial burden on the production cost of imaging member belts.

[0013] An advanced imaging member belt seaming technique has recently been successfully developed and demonstrated in recent years, by creating a puzzle-cut of male pattern at one end of an imaging member sheet and a matching puzzle-cut female pattern at the opposite end so that when butt joining them together by mating the puzzle-cut patterns and then secured the joint with application of an adhesive layer over it to form an endless flexible belt. Although this novel puzzle-cut seaming process represents a new breakthrough seaming technology and offers great promise, however the seam formed still has some physical, mechanical, and dimensional shortfalls yet remained to be overcome.

[0014] Therefore, there is an urgent need to provide seamed flexible imaging belts with an improved seam morphology which can withstand greater dynamic fatigue conditions thereby extending belt service life. It is also important, from the imaging member belt production point of view, that effective cutting of unit manufacturing cost of seamed imaging belts can be realized if an innovative post seaming treatment process can be developed for puzzle-cut seam joint improvement that overcomes the shortfalls and provides the triple benefits of seam region thickness reduction, seam surface morphological smoothing, and good mechanical seam strength.

[0015] U.S. Pat. No. 5,552,005 to Mammino et al., issued Sep. 3, 1996, discloses a flexible imaging sheet and a method of constructing a flexible imaging sheet. The method of constructing a flexible imaging sheet comprises a step of overlapping, a step of joining, and a step of shaping. In the step of overlapping, a first marginal end region and a second marginal end region of a sheet are overlapped to form an overlap region and a non-overlap region. In the step of joining, the first marginal end region and the second marginal end region of the sheet are joined to one another by a seam in the overlap region. In the step of shaping, the overlap region is shaped to form a generally planar surface co-planar with a surface of the non-overlap region. The flexible imaging sheet comprises a first marginal end region and a second marginal end region. The first marginal end region and the second marginal end region are secured by a seam to one another in the overlap region. The first marginal end region and the second marginal end region are substantially co-planar to minimize stress on the flexible imaging sheet. Minimization of stress concentration, resulting from dynamic bending of the flexible imaging sheet during cycling over a roller within an electrophotographic imaging apparatus, is particularly accomplished in the present invention.

[0016] U.S. Pat. No. 4,410,575 to Obayashi et al., issued Oct. 18, 1983, discloses that textile fabrics are firmly lap welded to each other by superposing two end portions of one or two fabrics on each other while interposing a piece of a synthetic polymeric bonding tape between the superposed two end portions and by applying a high frequency wave treatment and/or heat treatment to the interposed portion of the bonding tape through at least one of the superposed end portions while pressing them, to melt the interposed portion of the bonding tape thereby lap welding the end portions of the fabric or fabrics to each other.

[0017] U.S. Pat. No. 4,883, 742 to Wallbillich et al., issued Nov. 28, 1989, discloses a process for seamless and firm joining of the end and/or lateral areas of thermoplastically processible photosensitive layers, by which the end and/or lateral areas of one or more solvent-free and unsupported thermoplastically processible photosensitive layers are overlapped avoiding bubbles and with displacement of the air between the end and/or lateral areas, the total layer material is then heated under pressure and with joining of the overlapping end and/or lateral areas, and the resulting continuously joined photosensitive layer is then after treated and smoothed with shaping to exact size.

[0018] U.S. Pat. No. 4,532,166 to Thomsen et al., issued Jul. 30, 1985, discloses a welded web which is prepared by overlapping a first edge over a second edge, then applying heat necessary to bond the first edge with the second edge. The heating techniques may include ultrasonic welding, radio frequency heating, and the like.

[0019] U.S. Pat. No. 3,988,399 to Evans, issued Oct. 26, 1996, discloses heat recoverable articles which have an elongate S-shaped configuration, which later can be wrapped about a substrate. The articles comprise a molecularly oriented unitary polymeric layer which has been differentially annealed while restrained against dimensional change and crosslinking.

[0020] The disclosures of the foregoing U.S. patents to Mammino, Obayashi, Wallbillich, Thomsen and Evans are hereby incorporated by reference verbatim, with the same effect as though such disclosures were fully and completely set forth herein.

[0021] Moreover, the above-identified commonly-assigned application Ser. No. 08/721,418 to Edward L. Schlueter, Jr. et al. discloses producing an endless flexible belt using a punch and die. The disclosed punch and die have patterned edges in the form of a puzzle-cut pattern with extremely small nodes and kerfs. Moreover, the cutting tolerances of the patterned edges make it necessary to fix the punch with respect to the die so that there is no misalignment of the punch and the die between cutting operations.

[0022] While the above references disclose a variety of approaches to improve the seam of flexible belts, these disclosed approaches are either insufficient to meet the expectation, or often time introduce new set of undesirable outcomes. For example, puzzle-cut butt joined seam, based on intimate male-female puzzle pattern interlocking, though does provide a belt with a seam of nearly no additional thickness, however the seam is seen to pop open and separate when the butt joint puzzle-cut seam of the flexible imaging belt bends and flexes over small diameter belt support rollers, such as the 19 mm diameter roller, causing total seam separation. Attempts to apply a thin adhesive strip over the puzzle-cut seam joint to permanently secure the joint and resolve the seam bending induced popping problem has been successfully demonstrated, but the application of the adhesion does add significant thickness to the resulting puzzle-cut seam to thereby diminish the practical value of the seam.

[0023] Therefore, there is a need for an improved method for fabricating a flexible imaging member belt with a puzzle-cut seam having nil or reduced seam thickness.

SUMMARY OF THE INVENTION

[0024] Therefore, it is an object of the present invention to provide a method for fabricating an improved flexible electrostatographic imaging member belt which overcomes the above-noted deficiencies.

[0025] It is another object of the present invention to provide a process for flexible electrostatographic imaging member belt puzzle-cut seam joint treatment which yields a thinner seam morphology as well as improving its mechanical seam strength.

[0026] It is still another object of the present invention to provide a process for flexible electrostatographic imaging member belt puzzle-cut seam treatment which eliminates the need of an adhesion strip, yields a seam of nil thickness, and is free of fatigue belt bending induced seam popping/separation problem when the electrostatographic imaging member belt flexes over small diameter belt module support rollers during cycling belt function.

[0027] It is a further object of the present invention to provide a method for fabricating an improved flexible electrostatographic imaging member belt having a mechanically robust puzzle-cut seam and exhibiting good circumferential dimension tolerance as well as wrinkle free in the seam region.

[0028] It is a still further object of the present invention to provide a method for fabricating an improved flexible electrostatographic imaging member belt having a thin puzzle-cut seam and free of wrinkles in the region of the seam.

[0029] In one embodiment, the present invention comprises a method for fabricating a flexible imaging member belt with a puzzle-cut seam, the flexible belt having an outer belt surface, an inner belt surface, a first end terminating in a first set of puzzle-cut fingers, a second end terminating in a second set of matching puzzle-cut fingers, a length therebetween, the first and second sets of puzzle-cut fingers arranged to be joined together, the method comprising the steps of:

[0030] physically joining the first and second sets of puzzle-cut fingers to form a juncture of interlocking of these matching fingers;

[0031] apply a narrow adhesive strip over the outer belt surface only sufficiently enough to substantially cover the juncture, the adhesive strip comprising an adhesive surface;

[0032] compress the adhesive surface and the inner belt surface together at a point proximate to the juncture and, while compressing:

[0033] heat the adhesive layer for a fixed heating period to facilitate penetration or flow of the adhesive material into and fill the crevice between the fingers to secure the seam joint;

[0034] cool the adhesive layer for a fixed cooling period; and

[0035] determine when a puzzle-cut seam formed by the foregoing steps is satisfactory.

BRIEF DESCRIPTION OF THE DRAWINGS

[0036]FIG. 1 shows a flexible belt 10 with a puzzle-cut seam 11 fabricated in accordance with the present invention.

[0037]FIG. 1A shows the belt 10 and puzzle-cut seam 11 in greater detail.

[0038]FIG. 2 shows a cross-sectional profile of a narrow adhesive strip application over seam 11 of the belt 10 and apparatus 201-202 suitable for demonstrating one embodiment of the present invention.

[0039]FIG. 3 shows a cross-sectional profile of a narrow adhesive strip application over seam 11 of the belt 10 and apparatus 201-302 suitable for demonstrating a further embodiment of the present invention.

[0040]FIG. 4 shows a cross-sectional profile of seam 11 of belt 10 and apparatus 201A-302A suitable for demonstrating a still further embodiment of the present invention.

[0041]FIG. 5 is a flow diagram of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] Referring now to FIG. 1, there is shown a flexible imaging member belt 10 with a first end 103 and a second end 105, the two ends 103 and 105 being joined by a puzzle-cut seam 11 fabricated in accordance with the present invention. As shown, the length of flexible belt 10 extending between the two ends 103 and 105 is mounted on rollers 12. A drawing similar to FIG. 1 may be found in Lucille M. Sharf et al., “Puzzle cut seamed belt with bonding between adjacent surfaces by UV cured adhesive,” U.S. Pat. No. 5,487,707, issued Jan. 30, 1996, the disclosure of which U.S. patent is hereby incorporated by reference verbatim, with the same effect as though such disclosure were fully and completely set forth herein.

[0043]FIG. 1A shows greater detail of a specific segment of the flexible belt 10, particularly including the vicinity of the seam 11. As shown therein, flexible belt 10 comprises parallel edges 1-2 and the seam 11 extending from one edge to the other edge, the belt seam 11 including a seam region including a puzzle-cut butt joint with an applied adhesive strip 109 over the seam joint, the adhesive strip comprising a thermoplastic polymer material having a fusing temperature.

[0044] Still referring to FIG. 1A, the flexible belt 10 has an outer belt surface 10A, an inner belt surface 10B, a first end 103 terminating in a first set of puzzle-cut fingers 113, and a second end 105 terminating in a second set of matching puzzle-cut fingers 115. As shown, the finger sets 113 and 115 are arranged to mutually mate or join with each other.

[0045] In accordance with the present invention, the ends 103 and 105 are joined by means of mating finger sets 113 and 115 together. As a result of this joining, the now-mated finger sets 113 and 115 form a juncture 108.

[0046] Next, in accordance with the invention, an adhesive strip 109 is applied to over the juncture 108.

[0047] Subsequent steps of the invention are depicted in FIGS. 2-3.

[0048] Referring now to FIG. 2, there is shown a cross-sectional profile of the belt 10 together with apparatus 201-202 suitable for demonstrating one embodiment of the present invention. As shown, the adhesive strip 109 (a thermally activated material) is applied onto the outer belt surface 10A to only sufficiently enough cover the juncture 108. The adhesive strip 109 comprises an adhesive surface 109A. There is also shown two elements 201-202, the first element 201 comprising a compressing and heating element, and the second element 202 comprising a compressing element.

[0049] In accordance with the invention, the compressing and heating element 201 applies a first force to the adhesive surface 109A while, simultaneously, the compressing element 202 applies an equal but opposing second force to the inner belt surface 10B of the belt 10 at an area proximate to the juncture 108. As a result of the foregoing opposing first and second forces, adhesive surface 109A and part of inner belt surface 10B near the juncture 108 are compressed together. While elements 201 and 202 continue to actively apply the foregoing compressing forces, the following events occur, in sequence:

[0050] First, compression and heating element 201 applies heat directly to the adhesive surface 109A to heat up and soften or melt the adhesive strip 109 for a fixed heating period causing the adhesive material to flow into and fill the crevice between the mating fingers and bond the interfaces of these fingers, as well as promoting the adhesive to stick to the outer belt surface 10A at the juncture 108.

[0051] Second, after the above heating period, compressing and heating element 201 cools the adhesive layer 109 for a fixed cooling period.

[0052] Third, after the above fixed cooling period, a processor (not shown) determines when a puzzle-cut seam 11 resulting from the foregoing compressing, heating, and cooling applied to adhesive layer 109 is satisfactory.

[0053] If the puzzle-cut seam 11 is determined to be satisfactory, then elements 201 and 202 cease to apply the foregoing compressing forces, and the process of fabricating a flexible belt with a puzzle-cut seam is done.

[0054] Otherwise, if the puzzle-cut seam 11 is determined to be not satisfactory, then elements 201 and 202 will continue the processing cycle again, to apply the foregoing compressing forces, while the above heating, cooling, and determining steps repeat until the determining step determines that the puzzle-cut seam 11 is satisfactory. As above, once the puzzle-cut seam 11 is determined to be satisfactory, then elements 201 and 202 cease to apply the foregoing compressing forces, and the process of fabricating a flexible belt with a puzzle-cut seam is done. When the puzzle-cut seam treatment process needs multiple heat/cooling cycles to reach a satisfactory result, the cumulative treatment time is required, from effective belt production cost consideration, not to exceed 30 seconds.

[0055] In one embodiment, the above determining step includes a step of determining the total heating period during which the adhesive layer 109 has been heated.

[0056] In one embodiment of FIG. 2, the compressing pressure applied to adhesive strip 109 is between about 40 pounds per square inch and about 80 pounds per square inch.

[0057] In one embodiment of FIG. 2, the heat applied to adhesive strip 109 is at a temperature of between about 70 degrees Celsius and about 100 degrees Celsius.

[0058] In one embodiment of FIG. 2, the total heating period during which adhesive layer 109 is heated is at the desired temperature of between about 5 seconds and 25 seconds.

[0059] In one embodiment of FIG. 2, the adhesive strip 109 has a width that is sized to only sufficiently enough cover the juncture 108. In one embodiment, the width is approximately ranging from about 1 millimeter to about 10 millimeters.

[0060] In one embodiment, the cooling step is accomplished by cooling the compressing and heating element 201 with a cooling fluid.

[0061] In one embodiment, the cooling fluid is water.

[0062] In one embodiment, the flexible belt 10 comprises a photoreceptor belt.

[0063] In another embodiment, the flexible belt 10 comprises an electroreceptor belt.

[0064] In still another embodiment, the flexible belt 10 comprises an intermediate image transfer belt.

[0065] Referring now to FIG. 3, there is shown a profile of the belt 10 together with apparatus 201 and 302 suitable for demonstrating a further embodiment of the present invention.

[0066] Similar to the prior embodiment described immediately above, the adhesive strip 109 is applied onto the outer belt surface 10A to only sufficiently enough cover the juncture 108, the adhesive strip 109 comprising an adhesive surface 109A. Element 201 comprises a first compressing and heating element. As well, element 302 comprises a second compressing and heating element.

[0067] After the adhesive strip 109 has been applied to the outer belt surface 10A, the first compressing and heating element 201 applies a first force to the adhesive surface 109A while, simultaneously, the second compressing and heating element 302 applies a second force to the inner belt surface 10B at a point proximate to the juncture 108. As a result of the foregoing first and second forces, adhesive surface 109A and part of inner belt surface 10B near the juncture 108 are compressed together. Simultaneously while elements 201 and 302 continue to actively maintain the foregoing compressing forces, the following events occur in sequence:

[0068] The first compressing and heating element 201 applies heat directly to the adhesive surface 109A while, simultaneously, the second compressing and heating element 302 applies heat directly to the junction 108 and, in turn, to the bottom surface 109B of the adhesive strip 109, the combined heating provided by elements 201 and 302 thus heating the adhesive strip 109 for a fixed heating period.

[0069] After the above heating period, the first compressing and heating element 201 directly cools the adhesive surface 109A while, simultaneously, the second compressing and heating element 302 directly cools the junction 108 and, in turn, the bottom surface 109B of the adhesive layer 109, the combined cooling provided by elements 201 and 302 thus cooling the adhesive strip 109 for a fixed cooling period.

[0070] After the above fixed cooling period, a processor (not shown) determines when a puzzle-cut seam 11 resulting from the foregoing compressing, heating, and cooling applied to adhesive layer 109 is satisfactory.

[0071] If the puzzle-cut seam 11 is determined to be satisfactory, then elements 201 and 302 cease to apply the foregoing compressing forces, and the process of fabricating a flexible belt with a puzzle-cut seam is done.

[0072] Otherwise, if the puzzle-cut seam 11 is not determined to be satisfactory, then elements 201 and 202 will continue the processing cycle to apply the foregoing compressing forces, while the above heating, cooling, and determining steps repeat until the determining step determines that the puzzle-cut seam 11 is satisfactory. As above, once the puzzle-cut seam 11 is determined to be satisfactory, then elements 201 and 202 cease to apply the foregoing compressing forces, and the process of fabricating a flexible belt with a puzzle-cut seam is done.

[0073] In the FIG. 3 embodiment, compression and heating by elements 201 and 302 result in heating and softening or melting the adhesive strip 109 for a fixed heating period causing the adhesive material to flow into and fill the crevice between the mating fingers and bond the interfaces of these fingers, as well as promoting the adhesive to stick to the outer belt surface 10A at the juncture 108.

[0074] In one embodiment, the above determining step includes a step of determining the total heating period during which the adhesive strip 109 has been heated by the compressing and heating element 201.

[0075] In one embodiment of FIG. 3, the compressing pressure applied to adhesive strip 109 is between about 40 pounds per square inch and about 80 pounds per square inch.

[0076] In one embodiment of FIG. 3, the heat applied to adhesive strip 109 is at a temperature of between about 70 degrees Celsius and about 100 degrees Celsius.

[0077] In one embodiment of FIG. 3, the total heating period during which adhesive layer 109 is heated at a selected temperature is between about 5 seconds and about 25 seconds.

[0078] In one embodiment of FIG. 3, the adhesive strip 109 has a width that is sized to only sufficiently enough cover the juncture 108. In one embodiment, the width is approximately in a range of from about 1 millimeter to about 10 millimeters.

[0079] In one embodiment, the cooling step is accomplished by cooling the compressing and heating elements 201 and 302 with a cooling fluid.

[0080] In one embodiment, the cooling fluid is water.

[0081] In one embodiment, the flexible belt 10 comprises a photoreceptor belt.

[0082] In another embodiment, the flexible belt 10 comprises an electroreceptor belt.

[0083] In still another embodiment, the flexible belt 10 comprises an intermediate image transfer belt.

[0084] After performing the process based on FIG. 2 or FIG. 3, in one embodiment, a mechanical polishing step is performed to remove the adhesive from the outer belt surface 10A and smooth out the seam profile, thus achieving nil differential seam thickness in the treated puzzle-cut seam. Referring now to FIG. 4, there is shown a still further embodiment of the present invention. As shown, the puzzle-cut seam 11 is subjected to the compression/heating treatment process of elements of 201A and 302A in the same manners as that described in FIG. 3, with the exception that the adhesive strip 109 is not required and both the compression/heating elements 201A and 302A are reduced in cross-sectional area to have a width only sufficiently enough to cover juncture 108. For good understanding, the basic difference between elements 201A and 302A in FIG. 4 and the corresponding elements 201 and 302 in FIG. 3 is their respective shapes.

[0085] In the FIG. 4 embodiment, compression and heating by elements 201A and 302A result in heating and softening the belt 10 thermoplastic material to cause contacting surface areas of the fingers 113 and 115 to fuse together to form the puzzle-cut seam 11.

[0086] In one embodiment of FIG. 4, the compressing pressure applied to form seam 11 is between about 70 pounds per square inch and about 120 pounds per square inch. In one embodiment of FIG. 4, the heat applied to form seam 11 is at a temperature of between about 160 degrees Celsius and about 240 degrees Celsius.

[0087] In one embodiment of FIG. 4, the total heating period required to form seam 11, at the selected temperature, is between about 1 second and about 7 seconds.

[0088] Referring now to FIG. 5, there is shown a flow diagram of the present invention and the seam treatment process is carried out according to the steps below.

[0089] The steps of FIG. 5 will vary somewhat depending on which embodiment of the invention is being practiced.

[0090] The following first description is based on FIGS. 2 and 3.

[0091] After starting, step 501, the process goes to step 503.

[0092] In step 503, the first set 113 and second set 115 of puzzle-cut fingers of belt 10 are joined to form the juncture 108. The process then goes to step 505.

[0093] In step 505, an adhesive strip 109 is applied on the outer belt surface 10A to substantially cover the juncture 108, the adhesive 109 layer comprising an adhesive surface 109A. The process next goes to step 507.

[0094] In step 507, the adhesive surface 109A and the inner belt surface 10B are compressed together at a point proximate to the juncture 108. In one embodiment, the step 507 compressing forces of are applied by the compressing and heating element 201 and the compressing element 202. In another embodiment, the step 507 compressing forces are applied by a first compressing and heating element 201 and a second compressing and heating element 302.

[0095] While the step 507 compressing forces continue to be applied, the process goes to step 509.

[0096] In step 509, the adhesive layer 109 is heated for a fixed heating period. In one embodiment, the step 509 heat is applied by means of compressing and heating element 201 applying heat to the adhesive surface 109A. In another embodiment, the step 509 heat is applied by means of compressing and heating element 201 applying heat to the adhesive surface 109A and, simultaneously, compressing and heating element 302 applying heat to the junction 108 and, in turn, to the bottom 109B of the adhesive strip 109. In either embodiment, the adhesive strip 109 becomes heated. While the step 507 compressing forces continue to be applied, the process goes to step 511.

[0097] In step 511, the adhesive layer 109 is cooled for a fixed cooling period. In one embodiment, the step 511 cooling is applied by means of compressing and heating element 201 cooling the adhesive surface 109A. In another embodiment, the step 511 cooling is applied by means of compressing and heating element 201 cooling the adhesive surface 109A and, simultaneously, compressing and heating element 302 cooling the junction 108 and, in turn, the bottom 109B of the adhesive strip 109. In either embodiment, the adhesive strip 109 becomes cooled. While the step 507 compressing forces continue to be applied, the process goes to step 513.

[0098] In step 513, it is determined when the puzzle-cut seam 11 formed as a result of the foregoing adhesive layer applying step 505, compressing step 507, heating step 509 and cooling step 511 is satisfactory.

[0099] When determining step 513 determines that the puzzle-cut seam 11 is not satisfactory, the process returns to step 509, whereupon the heating step 509, cooling step 511, and determining step 513 are repeated.

[0100] Otherwise, when determining step 513 determines that the puzzle-cut seam 11 is satisfactory, the process goes to step 515.

[0101] In step 515, the compressing initially begun in the prior step 507 now ceases. The puzzle-cut seam 11 is now complete, and the process ends, step 517.

[0102] In one embodiment, the determining step 513 includes a step of determining a total (cumulative) period during which the adhesive layer 109 has been heated.

[0103] In accordance with the present invention, the physically interlocked butt joined puzzle-cut end 103 comprising the first set of puzzle-cut fingers 113 and the end 105 comprising the second set of puzzle-cut fingers 115 are processed into a boned seamed flexible imaging member belt 10, with puzzle-cut seamed joint 11.

[0104] In practice, the heating step 509 raises the temperature of the adhesive strip 109 in the joint region 108 to a temperature of from about 2-20 degrees Celsius above the fusing temperature of the thermoplastic polymer material that comprises the adhesive strip 109.

[0105] Also, the compressing step 507 combines with heating step 509 to flatten-out the adhesive strip 109, to eliminate protrusion spots in the adhesive strip 109, to reduce joint region thickness of the adhesive layer 109, as well as fusing the adhesive strip 109 to the juncture 108, thus resulting in a seamed flexible belt 10.

[0106] The meaning of fusing temperature of thermoplastic polymer material is defined here as an elevated temperature at which the thermoplastic polymer material at the belt juncture 108 is adequately softened to fuse into one continuous material matrix when subjected to the specific compressing force applied by step 507.

[0107] The following second description is based on FIG. 4.

[0108] After starting, step 501, the process goes to step 503.

[0109] In step 503, the first set 113 and second set 115 of puzzle-cut fingers of belt 10 are joined to form the juncture 108. The process then omits step 505 and goes directly to step 507.

[0110] In step 507, the outer belt surface 10A and the inner belt surface 10B in the vicinity of the juncture 108 are compressed together.

[0111] Next, while the step 507 compressing forces continue, the process goes in sequence to steps 409, 411 and 413.

[0112] In step 509, the belt in the vicinity of the juncture 108 is heated for a fixed heating period.

[0113] In step 511, the belt in the vicinity of the juncture 108 is cooled for a fixed cooling period.

[0114] In step 513, it is determined when the puzzle-cut seam 11 formed as a result of the foregoing compressing step 507, heating step 509 and cooling step 511 is satisfactory.

[0115] When determining step 513 determines that the puzzle-cut seam 11 is not satisfactory, the process returns to step 509, whereupon the heating step 509, cooling step 511, and determining step 513 are repeated.

[0116] Otherwise, when determining step 513 determines that the puzzle-cut seam 11 is satisfactory, the process goes to step 515.

[0117] In step 515, the compressing initially begun in the prior step 507 now ceases. The puzzle-cut seam 11 is now complete, and the process ends, step 517.

[0118] In one embodiment, the determining step 513 includes a step of determining a total (cumulative) period during which the juncture 108 has been heated.

[0119] In summary, there is provided a method in accordance with FIG. 5 for fabricating a flexible belt 10 with a puzzle-cut seam 11, the flexible belt having an outer belt surface 10A, an inner belt surface 10B, a first end 103 terminating in a first set of puzzle-cut fingers 113, a second end 105 terminating in a second set of matching puzzle-cut fingers 115, a length therebetween, the first 113 and second 115 sets of puzzle-cut fingers arranged to be joined together, the method comprising the steps of:

[0120] in step 503, joining the first and second sets of puzzle-cut fingers to form a juncture 108;

[0121] in step 505, applying an adhesive strip 109 on the outer belt surface to cover the juncture, the adhesive strip comprising an adhesive surface 109A;

[0122] in step 507, compressing the adhesive surface 109A and the inner belt surface 10B together at a point proximate to the juncture 108 and, while compressing:

[0123] in step 509, heating the adhesive layer 109 for a fixed heating period;

[0124] in step 511, cooling the adhesive layer 109 for a fixed cooling period; and

[0125] in step 513, determining when the puzzle-cut seam 11 formed by the foregoing joining, applying, compressing, heating and cooling steps is satisfactory.

[0126] Also, there is provided method in accordance with FIG. 5 for fabricating a flexible belt 10 with a puzzle-cut seam 11, the flexible belt having an outer belt surface 10A, an inner belt surface 10B, a first end 103 terminating in a first set of puzzle-cut fingers 113, a second end 105 terminating in a second set of matching puzzle-cut fingers 115, a length therebetween, the first 113 and second 115 sets of puzzle-cut fingers arranged to be joined together, the method comprising the steps of:

[0127] in step 503, joining the first and second sets of puzzle-cut fingers to form a juncture 108;

[0128] in step 507, compressing the outer belt surface 10A and the inner belt surface 10B together in the vicinity of the juncture 108 and, while compressing:

[0129] in step 509, heating the belt 10 in the vicinity of the juncture 108 for a fixed heating period;

[0130] in step 511, cooling the belt 10 in the vicinity of the juncture 108 for a fixed cooling period; and

[0131] in step 513, determining when the puzzle-cut seam 11 formed by the foregoing joining, compressing, heating and cooling steps is satisfactory.

[0132] In one embodiment, the equipment used to practice the present invention comprises an impulse heat sealing machine.

[0133] In one embodiment, the resulting puzzle-cut seam 11 is mechanically polished to remove the excess adhesive from the seam region surface to yield a resulting puzzle-cut seam joint having no added thickness. In one embodiment, polishing is done by applying abrasives to the joint surface.

[0134] The FIG. 5 process results in a seamed flexible belt of nil seam thickness and free of belt ripples at the vicinity of the puzzle-cut seam joint. It will be understood that the FIG. 5 adhesive applying step 505 is performed when the invention is practiced based on FIG. 2 or 3, but omitted when the invention is practiced based on FIG. 4.

[0135] In all embodiments of the invention, the compression, heating, and cooling cycles should be completed in less than 30 seconds based on effective belt production cost consideration as well as to yield good physical/mechanical and seam morphological results.

[0136] Further, there is provided a process for flexible electrostatographic imaging member belt puzzle-cut seam joint treatment which yields a thinner seam morphology as well as improving its mechanical seam strength.

[0137] Also, there is provided a process for flexible electrostatographic imaging member belt puzzle-cut seam treatment which eliminates the need of an adhesion strip, yields a seam of nil thickness, and is free of fatigue belt bending induced seam popping and separation problem when the electrostatographic imaging member belt flexes over small diameter belt module support rollers during cycling belt function.

[0138] Moreover, there is provided a method for fabricating an improved flexible electrostatographic imaging member belt having a mechanically robust welded seam and exhibiting good circumferential dimension tolerance as well as wrinkle free in the seam region.

[0139] Also, there is provided a method for fabricating an improved electrostatographic imaging member belt having a thin puzzle-cut seam and no wrinkles in the region of the seam.

[0140] While various embodiments of a method for fabricating a flexible belt with a puzzle-cut seam, in accordance with the present invention, have been disclosed hereinbove, the scope of the invention is defined by the following claims. 

What is claimed is:
 1. A method for fabricating a flexible belt with a puzzle-cut seam, the flexible belt having an outer belt surface, an inner belt surface, a first end terminating in a first set of puzzle-cut fingers, a second end terminating in a second set of matching puzzle-cut fingers, a length therebetween, the first and second sets of puzzle-cut fingers arranged to be mated and joined together, the method comprising the steps of: join the first and second sets of puzzle-cut fingers to form a juncture; apply an adhesive strip on the outer belt surface to cover the juncture, the adhesive strip comprising an adhesive surface; compress the adhesive surface and the inner belt surface together at a point proximate to the juncture and, while compressing: heat the adhesive layer for a fixed heating period to melt and fill a crevice between the mated fingers; cool the adhesive layer for a fixed cooling period; and determine when a puzzle-cut seam formed by the foregoing joining, applying, compressing, heating and cooling steps is satisfactory.
 2. The method of claim 1 where the adhesive strip has a width that is sized to only sufficiently enough cover the juncture.
 3. The method of claim 2 , where the width is approximately between about 1 millimeter and about 10 millimeters.
 4. The method of claim 1 , where the compressing step comprises a pressure of approximately between about 40 pounds per square inch and about 80 pounds per square inch.
 5. The method of claim 1 , where the heating step comprises a temperature of approximately between about 70 degrees Celsius and about 100 degrees Celsius.
 6. The method of claim 1 including repeating the heating, cooling and determining steps until the determining step determines that the puzzle-cut seam is satisfactory.
 7. The method of claim 6 , including a step of ceasing the compressing when the determining step determines that the puzzle-cut seam is satisfactory.
 8. The method of claim 1 , where the determining step includes a step of determining a total period during which the adhesive layer has been heated.
 9. The method of claim 1 , the heating step including a step of applying heat to the adhesive surface.
 10. The method of claim 5 , the heating step including a step of applying heat to the inner belt surface at a point proximate to the juncture.
 11. The method of claim 1 , the heating applied by a heating element, the cooling step including a step of cooling the heating element with a fluid.
 12. The method of claim 11 , where the fluid is water.
 13. The method of claim 1 , including a subsequent step of polishing the treated or processed puzzle-cut seam.
 14. The method of claim 1 , the flexible belt comprising a photoreceptor belt.
 15. The method of claim 1 , the flexible belt comprising an electroreceptor belt.
 16. The method of claim 1 , the flexible belt comprising an intermediate image transfer belt.
 17. A method for fabricating a flexible belt with a puzzle-cut seam, the flexible belt having an outer belt surface, an inner belt surface, a first end terminating in a first set of puzzle-cut fingers, a second end terminating in a second set of matching puzzle-cut fingers, a length therebetween, the first and second sets of puzzle-cut fingers arranged to be mated and joined together, the method comprising the steps of: join the first and second sets of puzzle-cut fingers to form a juncture; compress the outer belt surface and the inner belt surface together in the vicinity of the juncture and, while compressing: heat the belt in the vicinity of the juncture for a fixed heating period; cool the belt in the vicinity of the juncture for a fixed cooling period; and determine when a puzzle-cut seam formed by the foregoing joining, compressing, heating and cooling steps is satisfactory.
 18. The method of claim 17 including repeating the heating, cooling and determining steps until the determining step determines that the puzzle-cut seam is satisfactory.
 19. The method of claim 18 , where the compressing step comprises a pressure of approximately between about 70 pounds per square inch and about 120 pounds per square inch.
 20. The method of claim 19 , where the heating step comprises a temperature of approximately between about 160 degrees Celsius and about 240 degrees Celsius.
 21. The method of claim 20 , where the heat is applied for a total heating period between about 1 second and about 7 seconds. 